The quote is better known than understood: “Once again, the facts of life have turned out to be Tory.”

Margaret Thatcher did not say it as a smug prime minister, surveying her achievements. It appears in a pamphlet published by her party in opposition in 1976, as Britain sought emergency help from the International Monetary Fund.

Nor is it a chest-beating cry for market freedom or the distillation of a policy manifesto. It is just a nod to reality, expressed more in sorrow than in anger. We tried the left’s utopian schemes, it seems to say, and look where we are. Let the adults clean up. Thatcher was then elected to put Labour’s two-card trick of Keynesian largesse and corporatist meddling out of its misery, and ours.

This is generally how Conservatives win and keep power. They do not rally voters to a positive programme, they step in when economic troubles break an overreaching Labour government; 1951, 1979 and 2010 conform to this pattern. They then extend their stay in office, less because the nation warms to them than because it fears a recidivist Labour. The Tories are more like troubleshooters, hired on contract, than a great cause or a political movement.

They can still win the general election in May, but only in this fashion. They must campaign as plodding guardians of good sense. They must talk up the risk posed by Labour, and talk down their own appetite for doing anything remotely interesting in the next parliament beyond the dreary slog of achieving budgetary balance. They do not need to give positive reasons to vote Tory — tax cuts, grand visions for taming Leviathan — they need to remove reasons not to. If all they do is bore the pants off Britain for the next three months, they will emerge with at least a plurality of seats in a hung parliament.

This lesser-of-two-evils approach has a good record historically, but the circumstances of this election are particularly propitious for it. Economic data has improved to make the case for continuity suddenly attractive. As recently as a year ago, that was not true; the Tories needed to offer something extra. Real incomes are finally catching up with growth in economic output and employment. There is a chance that consumer price inflation will fall to zero in the run-up to the election. For an incumbent party, this is a goldilocks economy: strong, but not so strong as to warrant a gamble on a new government.

The other propitious circumstance is David Cameron. No prime minister since Harold Macmillan has been so temperamentally geared to campaigning as the “safe” option. When critics say he does not believe in much, they are right. But the burden is on them to explain why this is a bad thing. For a certain kind of swing voter, groping nervously for his wallet as he looks at an unquiet world, Cameron’s beliefs are reassuringly milquetoast. He does not seem like a man who would noticeably improve the country — or trash it.

Whatever his colleagues say, Cameron is a proper Tory. A Tory does not care for ideas or even politics itself. They claim no singular moral insight, unlike Labour, and espouse no mission, unlike the free-marketeers who now pepper the Conservative benches. They often cannot even stand their own party. They are quiet, bland patriots who get involved in public life on the hunch that more excitable types would mess it up. A Tory is a funny compound of civic entitlement and intellectual humility.

The biggest threat to the party in May is its own un-Tory streak. Cameron’s campaign makes the case for stability, yes, but it also lapses into the strident and the visionary. There is big talk of tax cuts and state reform. There is a temptation to make a spectacular “retail offer” in the manifesto. This is all worthy but, politically, it is also needless bordering on dangerous. It complicates the Tories’ timeless virtue: bovine solidity.

There is political logic in the Tories’ recent move into a more aggressive posture. Ask them if they have gone too far in their fiscal pronouncements of late, and the response is sharp. “What has everyone been talking about for the last month?” asks an insider. The point is well taken. Everyone is talking about the economy — the party’s strongest subject — because the choice between the parties has widened. In November, it was not obvious that this would be an economy election.

But this can be pushed too far. Cameron’s advisers should tell him to be more Thatcherite, but in the 1976 sense. With a languid sigh, he should say that Labour governments mean well but end chaotically, and take a long spell in opposition to learn. In a cautious country, that line is enough to renew his premiership. Votes evaporate when he starts being interesting.

— Financial Times